The Americans with Disabilities Act (ADA) requires the removal of physical obstacles to those who are physically challenged. The stated objective of this legislation has increased public awareness and concern over the requirements of the physically challenged. Consequentially, there has been more emphasis in providing systems that assist such a person to access a motor vehicle, such as a bus or minivan.
A common manner of providing the physically challenged with access to motor vehicles is a ramp. Various ramp operating systems for motor vehicles are known in the art. Some slide out from underneath the floor of the vehicle and tilt down. Others are stowed in a vertical position and are pivoted about a hinge, while still others are supported by booms and cable assemblies. The present invention is generally directed to a “fold out” type of ramp. Such a ramp is normally stowed in a horizontal position within a recess in the vehicle floor, and is pivoted upward and outward to a downward-sloping deployed position. In the deployed position, the ramp is adjustable to varying curb heights.
Fold out ramps on vehicles confront a variety of technical problems. Longer ramps are desirable because the resulting slope is lower and more accessible by wheelchair-bound passengers. However, the ramp length is typically limited by the space available in the vehicle. Elements such as vehicle chassis structure, suspension, passenger seats, driver platforms, and fare boxes prohibit longer ramps. As a result the ramp slopes are steeper than desired, and although presently ADA compliant, are unmanageable by the mobility impaired without assistance. Further, longer ramps are heavier and require more torque about the pivot axis to be reciprocated between deployed and stowed positions. To satisfy this torque requirement, such fold out ramps use large electric motors, pneumatic devices, or hydraulic actuators to deploy and stow the ramp. Many of such systems cannot be moved manually in the event of failure of the power source unless the drive mechanism is first disengaged. Some existing fold out ramps can be deployed or stowed manually, but they are difficult to operate because one must first overcome the resistance of the drive mechanism.
Proposed changes to the ADA require that ramps should have overall slopes not steeper than 1:6 (17 percent) when deployed to boarding and alighting areas without station platforms and to the roadway. Typical ramps manufactured today are generally designed to provide a 1:4 (25 percent) slope when deployed. Although these ramps could be lengthened to provide a slope of 1:6 or less, as previously mentioned, longer ramps are heavier and require a greater actuation force. Moreover, longer ramps require a larger installation envelope within the vehicle floor. Thus, there exists a need for a compact fold out ramp that when stowed occupies a small amount of space within the vehicle floor, yet deploys to a length that effectively reduces the ramp slope encountered by the mobility impaired to a maximum rise to run ratio of 1:6 or less to facilitate greater independence and safety for wheelchair-bound passengers, and wherein the actuation forces to operate the ramp are minimized.